Edward Snowden writes open letter to Brazil saying he can help investigate
spying claims - but for something in return

Edward Snowden, the rogue US defence contractor, has offered to helpBrazil investigateAmerican spying programmes in exchange for being granted permanent political asylum.

In an "open letter to the Brazilian people", Snowden said he was willing to help the Brazilian government "where appropriate and legal" but said the US government would prevent him from acting unless he was granted asylum.

The former CIA contractor is currently in self-imposed exile in Russia where he fled after revealing the scope of the National Security Agency's spying programmes using stolen documents that he leaked to the Guardian and the New York Times.

Among the revelations were the mass collection of telephone metadata and the fact that the America government had intercepted communication by the Brazilian president Dilma Rousseff, as well as spying on the state-owned oil company Petrobras.

In the letter published by Folha de São Paulo, Mr Snowden said many Brazilian senators had "asked me to help with their investigations into suspected crimes against Brazilian citizens."

He added: "I've expressed my willingness to assist where it's appropriate and legal, but, unfortunately, the US government has been working hard to limit my ability to do so.

"Until a country grants me permanent political asylum, the US government will continue to interfere with my ability to speak out."

In October, Ms Rousseff cancelled a visit to Washington in the wake of the revelations, however offering Mr Snowden asylum would be a very serious step that the White House has made clear would damage US-Brazilian relations.

The White House this week ruled out any prospect of offering an amnesty to Mr Snowden after the idea was floated by a senior NSA officer in a television interview, with officials reiterating that Mr Snowden was a felon who should return to America to stand trial.

However the White House remains under intense pressure over the Snowden leaks – which this week had their first visible legal impact when a court in Washington ruled that the bulk collection of phone records was "Orwellian" and almost certainly unconstitutional.

The court's findings, which will be subject to appeal, were a blow to White House which had already instituted a presidential review of NSA practices in a bid to show that the administration was serious about addressing privacy issues in the wake of the Snowden leaks.

The review findings are due to be released in January, but early reports suggest it will not rule out intelligence agencies trawling phone metadata but subject the process to greater third-party scrutiny.

The Snowden affair has also damage the White House relations with Internet companies, including Yahoo! and Apple, who signed a letter last week calling for changes to US government surveillance practices.

The group of tech-company CEO's met with Mr Obama in the White House on Tuesday in a closed-door meeting at which companies representatives said they would press their case.

Mr Snowden had originally said his biggest fear when leaking the NSA documents was that his message would be ignored, praising the response of the Brazilian government to ensure that was not the case.

"Never before was I so happy to have been so wrong. The reaction in certain countries has been especially inspiring to me, and Brazil is one of them, no doubt," he said.

Glenn Greenwald, the former Guardian journalist who broke the story, is to campaign for the Brazilian president to grant Snowden political asylum.

Mr Greenwald, who lives in Rio with his partner David Miranda, said: "If the Brazilian government is grateful to his for the revelations, it's logical to protect him."

Brazil's Foreign Ministry told Folha it respected the sovereignty of other countries and would not enter a trading game.

The office of the president has not publicly responded to the letter as there has been no formal application for asylum.